The invention relates to an electric reflector lamp comprising:
a hollow moulded reflector body with an optical axis and a neck surrounding said optical axis; PA1 a lamp cap provided with contacts and connected to the neck; PA1 a light source which is arranged in the reflector body, is electrically connected to the contacts of the lamp cap by means of current conductors, and is accommodated in a lamp vessel having a seal; PA1 a metal mounting member in the neck which holds the lamp vessel and through which said seal of the lamp vessel is passed.
Such a reflector lamp is known from EP-A 0 543 448 (PHN 13.900).
The reflector body in the known reflector lamp is integral with the neck. The neck has a seat on which the mounting member bears. The mounting member is a plate through which the seal is passed and which has resilient tags which hold the seal of the lamp vessel with clamping force. The current conductors are fastened to a bottom of the neck under tension. Because of the thermal load and the ease of its manufacture, the reflector body is usually made of glass.
U.S. Pat. No. 5,281,889 discloses a reflector lamp whose neck is bipartite. The mounting member, again a plate with resilient tags which hold the seal with clamping force, is enclosed between the two parts of the neck.
U.S. Pat. No. 4,829,210 discloses a reflector lamp whose mounting member is a similar plate with resilient tags, but this plate has a flanged rim subdivided into resilient tags which rest with clamping force in the neck of the reflector body.
Such reflector lamps may be used as substitutes for incandescent lamps with blown glass bulbs for general lighting purposes or for such lamps having reflectorized blown bulbs. The reflector lamps may be operated at mains voltage and have Edison or bayonet caps. The intended application of the lamps implies that they must fit in conventional luminaires and that their necks must thus be comparatively long, corresponding to those of said lamps having blown bulbs.
The known reflector lamps have the advantage over conventional incandescent lamps that the light source is enclosed in an inner lamp vessel, and can thus have a higher brightness and a higher luminous efficacy, and can be more compact. As a result, the generated light can be shaped into a beam of comparatively high intensity in the centre thereof by the reflector body.
A disadvantage of these reflector lamps is, however, that the seal of the lamp vessel held by the mounting member assumes a comparatively high temperature during operation, although this seal is surrounded by a space inside the neck and in the direction of the lamp cap. The mounting member, however, closes off the space in the neck substantially from the space in the reflector body. A comparatively high temperature of said seal may limit lamp life. The current conductors in said seal may in fact oxidize comparatively quickly then, so that they cause the seal to crack.